body {
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f0f0f0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
  }
  
  .game-container {
    background: #e0e0e0;
    padding: 20px;
    border-radius: 20px;
    box-shadow: 10px 10px 20px #bebebe, -10px -10px 20px #ffffff;
    text-align: center;
    max-width: 90%;
  }
  
  h1 {
    margin-bottom: 20px;
    color: #333;
    font-size: 2.5em;
  }
  
  .difficulty {
    margin-bottom: 20px;
  }
  
  .difficulty button {
    padding: 10px 20px;
    margin: 5px;
    border: none;
    border-radius: 10px;
    background: #d0d0d0;
    box-shadow: 3px 3px 5px #bebebe, -3px -3px 5px #ffffff;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1em;
  }
  
  .difficulty button:hover {
    box-shadow: inset 3px 3px 5px #bebebe, inset -3px -3px 5px #ffffff;
  }
  
  .custom-difficulty {
    margin-top: 10px;
  }
  
  .custom-difficulty input {
    padding: 5px;
    margin: 5px;
    border: none;
    border-radius: 5px;
    background: #d0d0d0;
    box-shadow: inset 3px 3px 5px #bebebe, inset -3px -3px 5px #ffffff;
    font-size: 1em;
  }
  
  .custom-difficulty button {
    padding: 5px 10px;
    border: none;
    border-radius: 5px;
    background: #d0d0d0;
    box-shadow: 3px 3px 5px #bebebe, -3px -3px 5px #ffffff;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1em;
  }
  
  .custom-difficulty button:hover {
    box-shadow: inset 3px 3px 5px #bebebe, inset -3px -3px 5px #ffffff;
  }
  
  .info {
    margin-bottom: 20px;
    font-size: 1.2em;
    color: #333;
    display: flex;
    justify-content: space-between;
  }
  
  .board {
    display: grid;
    gap: 5px;
    margin-bottom: 20px;
  }
  
  .cell {
    width: 30px;
    height: 30px;
    background: #d0d0d0;
    border-radius: 5px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 14px;
    cursor: pointer;
    box-shadow: 3px 3px 5px #bebebe, -3px -3px 5px #ffffff;
    transition: all 0.2s ease;
  }
  
  .cell.revealed {
    background: #c0c0c0;
    box-shadow: inset 3px 3px 5px #bebebe, inset -3px -3px 5px #ffffff;
  }
  
  .cell.flagged {
    background: #ffcccb;
  }
  
  .controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  button {
    padding: 10px 20px;
    border: none;
    border-radius: 10px;
    background: #d0d0d0;
    box-shadow: 3px 3px 5px #bebebe, -3px -3px 5px #ffffff;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1em;
  }
  
  button:hover {
    box-shadow: inset 3px 3px 5px #bebebe, inset -3px -3px 5px #ffffff;
  }
  
  #status {
    font-size: 1.2em;
    color: #333;
  }
  /* 弹窗样式 */
  .popup {
    display: flex;
    justify-content: center;
    align-items: center;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
  }
  
  .popup-content {
    background: #e0e0e0;
    padding: 20px;
    border-radius: 20px;
    box-shadow: 10px 10px 20px #bebebe, -10px -10px 20px #ffffff;
    text-align: center;
    position: relative;
  }
  
  .close-popup {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 24px;
    cursor: pointer;
    color: #333;
  }
  
  .close-popup:hover {
    color: #000;
  }
  